The GABAA receptor protein complex is the molecular target of a number of ligands, including the benzodiazepine class of tranquilizer drugs. Multiple isoforms of the GABAA receptor exist; each receptor is a pentameric complex comprising subunits drawn from α1-6, β1-3, γ1-3, δ, ε, and θ subunit isoforms. However, the classical benzodiazepines show no subtype selectivity. Moreover it is believed that one of the key elements responsible for the drawbacks of the classical benzodiazepanes (such as sedation, dependency and cognitive impairment) has to do with the α1 subunit of the GABAA receptors.
Further, it has been suggested that the GABAA α5 subunit represents a therapeutic target for treatment of various diseases and disorders of the central nervous system, and literature has establish a nexus between the GABAA α5 subunit as therapeutic target, and various acute and chronic neurological discorders, chronic neurological disorders, cognitive disorders, Alzheimer's disease, memory deficits, schizophrenia, positive, negative and/or cognitive symptoms associated with schizophrenia, bipolar disorders, autism, Down syndrome, neurofibromatosis type I, sleep disorders, disorders of circadian rhythms, amyotrophic lateral sclerosis, dementia caused by AIDS, psychotic disorders, substance-induced psychotic disorder, anxiety disorders, generalized anxiety disorder, panic disorder, delusional disorder, obsessive compulsive disorders, acute stress disorder, drug addictions, movement disorders, Parkinson's disease, restless leg syndrome, cognition deficiency disorders, multi-infarct dementia, mood disorders, depression, neuropsychiatric conditions, psychosis, attention-deficit hyperactivity disorder, neuropathic pain, stroke, attentional disorders, eating disorders, anorexia, anorexia nervosa, cachexia, weight loss, muscle atrophy, pain conditions, chronic pain, nociceptive pain, post-operative pain, osteoarthritis pain, rheumatoid arthritis pain, musculoskeletal pain, burn pain, ocular pain, pain due to inflammation, pain due to bone fracture, hyperalgesia, neuropathic pain, herpes-related pain, HIV-related neuropathic pain, traumatic nerve injury, post-stroke pain, post-ischemia pain, fibromyalgia, chronic headache, migraine, tension-type headache, diabetic neuropathic pain, phantom limb pain, visceral pain and cutaneous pain, and compounds capable of modulating GABAA receptors containing the α5 subunit are in particular expected to be useful candidates for the treatment of i.a. cognitive disorders, Alzheimer's disease, schizophrenia, positive, negative and/or cognitive symptoms associated with schizophrenia, and cognitive deficits associated with Down syndrome, with autism, with neurofibromatosis type I, or after stroke.
Isoxazole derivatives capable of modulating the GABAA receptor complex are known from e.g. WO 2007/039389, WO 2007/042420, WO 2007/054444, WO 2007/071598, WO 2007/074078, WO 2007/074089, WO 2007/137954, WO 2009/000662, WO 2009/071464, WO 2009/071476, WO 2009/071477, WO 2010/097368, WO 2010/112475, WO 2010/125042, WO 2010/127968, WO 2010/127974, WO 2010/127975, WO 2010/127976 and WO 2010/127978, and triazole derivatives capable of modulating the GABAA receptor complex are known from e.g. WO 2012/062687. Moreover WO 2008/025539, WO 2008/025540, WO 2009/149795 and WO 2011/020615 describe heterocyclic compounds, including certain phenyl triazole derivatives, useful as agonists of the NR1 H4 (FXR) receptor. However, the triazole derivatives of the present invention have not been reported.